The Phase I research program described in this proposal will determine the feasibility of utilizing the laser microprobe mass analysis (LMMA) technique for the quantitative microanalytical characterization of biological materials. The specific aims of this program are to evaluate the microanalytical capability of the laser microprobe on performing localized, in-situ elemental and molecular analysis of biological specimens. The successful completion of this Phase I program will provide the basis for a Phase II search effort in which these microanalytical capabilities will be experimentally evaluated. The long-term objectives of this research program are 1) determine the dominant parameters which effect elemental and molecular detection sensitivity, 2) develop biological reference materials for laser microprobe analysis, 3) develop suitable sample preparation procedures, and 4) determine the microanalytical capability of the technique for a diverse range of biological materials. The achievement of these objectives will provide a sensitive microanalytical method for the characterization of biological materials which can be applied to biomedical research problems, pathological studies as well as diagnostic evaluation of patient's state-of-health.